Kinematographic apparatus

ABSTRACT

A system for uniformizing the speed at which a kinematographic film is wound round the take-up spool in a view-taking or projecting apparatus by means of a feeler engaging a loop formed by the film between the exposure gate and said spool. When ever the speed of winding excessively tensions the film passing out of the gate, the loop shrinks and the stops the spool either by opening a switch in the circuit feeding a driving motor or by mechanically acting on a roller or gear driving the spool For reversed progression a second roller or gear can be used which is similarly controlled by the feeler.

Thevenaz [45] Aug. 1, 1972 [54] KINEMATOGRAPHIC APPARATUS [72] Inventor:Jean Thevenaz, Grandson, Switzerland Assignee: Paillard S.A.,Sainte-Croix, Vaud,

Switzerland Filed: March 10, 1970 Appl. No.: 18,201

Foreign Application Priority Data Fh 2 21 -SL 92! @1215! US. Cl...242/189, 242/205 [51] Int. C1......B651I 59/38, G031) 1/04, G111!15/32 [58] Field of Search...242/189, 190, 182, 183,

207-2l0,242/75.5, 75.51; ZOO/61.18; 352/159, 166,

[56] References Cited UNITED STATES PATENTS 1,944,037 1/1934 Proctor..352/176 3,175,777 3/1965 Jones, Jr. ..242/190 3,448,668 6/ 1969 Nomuraet a1. ..352/174 X 1,153,887 9/1915 Blair ..242/189 3,181,805 5/1965Keznickl et a1. ..242/ 190 X Primary Examinen-Leonard D. ChristianAttorney-Emory L. Groff and Emory L. Groff, Jr.

[5 7] ABSTRACT A system for uniformizing the speed at which a kine- V, li atographic film is wound round the take-up spool in March 24, 1969Switggrland ..4364/69 1 a view-taking or projecting apparatus by meansof a feeler engaging a loop formed by the film between the exposure gateand said spool. When ever the speed of winding excessively tensions thefilm passing out of the gate, the loop shrinks and the stops the spooleither by opening a switch in the circuit feeding a driving motor or bymechanically acting on a roller or 7 gear driving the spool For reversedprogression a second roller or gear can be used which is similarlycontrolled by the feeler.

6 Claims, 3 Drawing Figures PATENTED 1 I972 3,680.81 1

INVENTOR ATTl R NFY PATENTEnAuc H972 3.680.811

sum 2 0F 2 INVENTOR BY away i KINEMATOGRAPHIC APPARATUS required for thetake-up spool. This results in a loss of power which cannot be neglectedin such a coupling since its output gear revolves at an angular speeddefined by the linear speed of progression of the film.

Furthermore, the torque transmitted to the spool by the coupling issubstantially constant and consequently the tensioning of the filmdecreases as the diameter of its winding increases. The tensioning ofthe film when wound varies thus and this affects detrimentally theuniformity of the winding.

. The present invention has for its object to reduce the power requiredfor driving the take-up spool, while improving the uniformity ofwinding.

More specifically, the invention covers a kinematographic apparatusincluding a film-guiding channel, means driving the film through thechannel and a takeup spool; the novelty of the invention including meansfor driving said spool in a pulsatory intermittent manner.

The accompanying drawing illustrates diagrammatically and by way ofexample three embodiments of the present invention; In said drawing:

FIG. 1 illustrates means driving the take-up spool by means of pulses inaccordance with the first embodiment of the invention.

FIG. 2 is a view illustrating a-second embodiment of an arrangementdriving the take-up spool by means of pulses.

FIG. 3 illustrates the third embodiment.

In the arrangement illustrated in FIG. 1, the film F as it passes out ofthe film guiding exposure channel 'or gate 1 facing the objective 2 ofthe apparatus describes a loop 3 of a variable length after which itpasses between two guiding rollers 4 and 5 and is wound round a take-upspool 6.

I An electric circuit 11 fed by 'a supply S includes a switch controlledby a feeler 7 constituted by a thin and yielding metal blade securedthrough its end 8 and an electric motor 9 adapted to drive through apinion and a toothed wheel the take-up spool 6.

The drive of said take-up spool is as follows:

When the loop 3 of the film F fed by the exposure channel reaches apredetermined length, it engages the yielding feeler 7 which, under thethrust exerted by the film, is lowered and moves in the direction of thearrow so as to rest through its free terminal section on thecontacvpiece 10 forming with the feeler the switch closing the electriccircuit 11. The motor 9 then starts and drives the take-up spool 6. Asthe latter stores more and more filmmaterial, the loop 3 becomes shorterandthe switch opens and deenergizes the circuit 11 since the loop nolonger exerts any pressure on the feeler 7 which returns into itsoriginal horizontal position. Consequently, the motor 9 stops until afurther increase in length of the loop formed by the film again producesa closing of the circuit, this procedure continuing intermittently inthe manner disclosed.

The oscillatory period of the arrangement depends on the mechanical andelectric data governing the different parts. It is possible to act onsaid data so as to provide, for instance, once a normal rhythm ofoperation is reached, for the closing and opening of the switch to beobtained at the frequency of the succession of the pictures by means ofthe alternating movements of the loop produced by the intermittentprogression of the film. The difference between the linear speed of thefilm and the tangential speed of the spool'is thus compensated by themore or less long periods of closing of the switch.

The driving arrangement illustrated in FIG. 2 includes a bell crank 12pivotally secured to a shaft 13.

Said bell crank 12 carries at one end a stud or projection'l4 acting asa loop-contacting feeler while its other end carries a roller 15 actingas a driving gear. A spring 16 acts on the bell crank 12 so as to urgethe roller 15 against the periphery of the flange of a spool 17. Theroller 15 is driven by a toothed wheel 18 rigid with the shaft 13 drivenin its turn by the motor of the kinematographic apparatus. Said wheel l8meshes with a toothed pinion 19 coaxially rigid with the roller 15.

In order to obtain a satisfactory operation of the projector the filmwhich has progressed behind the objective 20 should form a loop 21before it is wound around the spool 17.

The rotary speed of the roller 15 is sufficient for it to drive thespool 17 at a speed which is slightly higher than that required for thewinding of the film. Consequently, the loop 21 of the film shrinksduring the winding around the spool until the film actually engages thestud 14 on the bell crank 12. The film causes then the bell crank 12 torock against the action of the spring 16 so as to shift the roller 15away from the spool 17, which latter is no longer driven by said rollerand allows the loop to increase in size.

As soon as the loop 21 has become sufficiently large, the spring 16returns the bell crank into its original position so that the roller 15reengages the spool and drives it again. By reason of its inertia, thespool 17 does not stop suddenly when its drive is discontinued. Sincethe bell crank 12 moves speedily over a small angular distance, thisproduces a drive of the spool 17 by means of pulses providing a uniformaverage speed.

The embodiment illustrated in FIG. 3 includes the same components asthat illustrated in FIG. 2, together with further parts adapted to drivethe spool 17 in a reversed direction. To this end, an oscillating arm 22is pivotally secured independently of the bell crank 12 to the shaft 13.Said oscillating arm 22 carries at its free end a driving gearconstituted by a roller 23 driven in a direction opposed to the rotationof the roller 15 by an intermediate toothed wheel 27 meshing with thetoothed wheel 18 rigid with the shaft 13.

The bell crank 12 is operatively connected with the oscillating arm 22by means of a spring 24the ends of which are secured on the one hand toan arm of the bell crank 12 and on the other hand to a projection orstud 25 on the arm 22. Said spring 24 urges the stud 25 against a stop26 secured to one side of the bell crank 12.

The arrangement illustrated in FIG. 3 is of particular interest in thecase of kinematographic projectors since it affords means for reversalof the film without any reversal in the direction of rotation of themotor, as allowed by the shifting in time of the operation of the filmdriving claws.

In such projectors, the feed spool is driven by means similar to thosedriving the take-up spool. Both spool driving means are controlledsynchronously by the motor controlling the film driving claws.

The operation of the arrangement illustrated in FIG. 3 is the same forforward motion as that of the arrangement illustrated in FIG. 2. Forrearward operation providing a reversal of the progression of the film,the loop 21 shrinks, so that the film first engages the stud 14 so as tomake the bell crank 12 rock against the action of the spring 16, whichcauses the reversing roller 23 to move towards the spool 17.

As the film continues its rearward progression, the loop 21 continuesshrinking and the roller frictionally engages the spool 17 and drives itin the film unwinding direction.

The pivotal connection between the bell crank 12 and the arm 22 allowsthe bell crank 12 to continue rocking in spite of the arm 22 beingarrested by reason of the contacting between the roller 23 and spool 17.As soon as the speed of unwinding rises above the speed of its reversemovement in the exposure gate in registry with the objective 20, theloop 21 expands so that the roller 23 again moves away from the spool17.

According to an embodiment which is not illustrated, it is possible toprovide a metal blade for elastically connecting the bell crank 12 withthe stud 14. This would allow the roller to transmit in the caseillustrated in FIGS. 2 and 3 only the average value of the loop 21 ofthe film.

Iclaim:

1. In a film operating kinematographic camera, the combination of a filmguiding exposure gate, a take-up spool, means driving the film throughthe gate, means driving the take-up spool to wind the film passing outof the gate around said take-up spool at a rhythm of operation equal tothat of the gate, means for intermittently stopping the winding of thefilm to make the average speed of linear progression of the film on thespool match its linear progression through the gate, said film beingadapted to form a loop between the gate and the take-up spool, saidmeans driving the take-up spool including a roller engaging the take-upspool to ensure the winding of the film around the spool, saidintermittent film stopping means including a feeler engaging said loop,a member interconnecting said feeler with said roller and adapted tourge said roller away from the take-up spool whenever said loop shrinksto a predetermined extent.

2. The combination as claimed in claim 1 wherein said means for drivingthe take-up spool includes a second roller frictionally engaging saidtake-up spool alternately with said first mentioned roller tooperatively ensure respectively the winding and the unwinding of thefilm around the spool and the intermittent film stopping means include afeeler engaging said loop and adapted to urge the operative roller awayfrom the take-up spool and said member interconnects said feeler withboth of said rollers.

3. The combination as claimed in claim 1 wherein said means for drivingthe take-up spool includes a iiill ivltfi ii ii r nfn I31 835 03152392ly ensure respectively the winding and unwinding of the film around thespool, lever means carrying said rollers, a pivot around which saidlever means rocks to ensure the selective engagement of the rollers withthe take-up spool, a rotary gear carried by said pivot and controllingthe two rollers in opposite directions, said feeler pivotally carried bysaid pivot and urging the operative roller away from the take-up spoolwhenever said loop shrinks to a predetermined extent.

4. The combination as claimed in claim 3 and further including a studrigid with said lever means, a stop rigid with said feeler andcooperating with said stud to limit the angular spacing between saidfeeler and said lever means and a spring connecting the feeler and leverto urge them into a position for which the stud and stop are engaged.

5. The combination as claimed in claim 1 wherein said roller is carriedby said feeler.

6. The combination as claimed in claim 1 wherein said intermittent filmstopping means includes a bell crank, said feeler mounted at one end ofsaid bell crank and said roller mounted at the opposite end thereof anda spring urging said bell crank into a position whereby the rollerengages the take-up spool.

1. In a film operating kinematographic camera, the combination of a filmguiding exposure gate, a take-up spool, means driving the film throughthe gate, means driving the take-up spool to wind the film passing outof the gate around said take-up spool at a rhythm of operation equal tothat of the gate, means for intermittently stopping the winding of thefilm to make the average speed of linear progression of the film on thespool match its linear progression through the gate, said film beingadapted to form a loop between the gate and the take-up spool, saidmeans driving the take-up spool including a roller engaging the take-upspool to ensure the winding of the film around the spool, saidintermittent film stopping means including a feeler engaging said loop,a member interconnecting said feeler with said roller and adapted tourge said roller away from the take-up spool whenever said loop shrinksto a predetermined extent.
 2. The combination as claimed in claim 1wherein said means for driving the take-up spool includes a secondroller frictionally engaging said take-up spool alternately with saidfirst mentioned roller to operatively ensure respectively the windingand the unwinding of the film around the spool and the intermittent filmstopping means include a feeler engaging said loop and adapted to urgethe operative roller away from the take-up spool and said memberinterconnects said feeler with both of said rollers.
 3. The combinationas claimed in claim 1 wherein said means for driving the take-up spoolincludes a second roller frictionally engaging said take-up spoolalternately with said first mentioned roller to operatively ensurerespectively the winding and unwinding of the film around the spool,lever means carrying said rollers, a pivot around which said lever meansrocks to ensure the selective engagement of the rollers with the take-upspool, a rotary gear carried by said pivot and controlling the tworollers in opposite directions, said feeler pivotally carried by saidpivot and urging the operative roller away from the take-up spoolwhenever said loop shrinks to a predetermined extent.
 4. The combinationas claimed in claim 3 and further including a stud rigid with said levermeans, a stop rigid with said feeler and cooperating with said stud tolimit the angular spacing between said feeler and said lever means and aspring connecting the feeler and lever to urge them into a position forwhich the stud and stop are engaged.
 5. The combination as claimed inclaim 1 wherein said roller is carried by said feeler.
 6. Thecombination as claimed in claim 1 wherein said intermittent filmstopping means includes a bell crank, said feeler mounted at one end ofsaid bell crank and said roller mounted at the opposite end thereof anda spring urging said bell crank into a position whereby the rollerengages the take-up spool.